I am using the trial version of Sonar Artist.  I am plugging a Strat directly into a Scarlett 2i2. I have the Scarlett plugged into a Core I7 laptop. The Audio out of the Scarlett 2i2 is plugged into my Yamaha powered mixer. The direct monitor sounds fine. I hear the metronome during record and it sounds fine. The playback of the instrument is distorted sounding.  The metronome is clear as a bell.
It is not distorted like overdrive, but like a steady state distortion.
I had it the same set up plugged in yesterday except for the PA.  I had my computer desk speaker plugged into the headphone jack on my laptop. Everything sounded fine but there was very bad latency when recording. So I hooked it up tonight usinf the line out on the Scarlett.
It has to be something like the signal is going thru 2 different processors or something.  Any ideas?

If you plug in headphones to your Scarlett and listen to the playback of the instrument, does it sound distorted?
 
Are your levels clipping anywhere in your signal chain (track, master bus, output) in Sonar?
 
Can you adjust the gain on your PA mixer channels and eliminate the distortion?  Can you try a different channel on your PA mixer?

The Demo version does not save settings.  I had to work back through the Audio set up guide and set the correct drivers.

Did that correct your problem or are you still experiencing it?